HP71B ROM PAC "UDL-71*" by Viewtronics


Does anyone have info or knowledge of an HP-71B ROM PAC produced by Viewtronics in 1986 titled "UDL-71*"? I bought it to use an a 32k EPROM but it has five protected files on it. The ROM PAC may be useful to someone for its software. John Pierce


Hi John,

I have no special information on it, but I'm interested by the pac. Can you make a ROMCOPY to a disc image file (I know you have a PIL-Box :-)



Hello Jean-Francois, You have mail. John Pierce


Viewtronics was a monitor and terminal maker in the 80s. I purchased several of the inexpensive VTxxx compatible terminals they made when I was the computer manager at the UCSB Physics department. The company seems to be defunct. The domain name is registered to an individual in Ahrensburg, Germany, but no name server answers for a query on "www.viewtronics.com" or "viewtronics.com." Reading the wikipedia entry on ViewSonics, it is clear that company is not a successor or otherwise related to Viewtronics.

I'd be interested to know what that module is about. The obvious thing would be if it contained a driver for a Viewtronics terminals. Regardless, it should be interesting.


Thanks to John, I was able to have a look at the ROM PAC.

The ROM is mainly made of a large BASIC program that deals with files, the Wand, and HP-IL devices (the well known "HP82164A" interface, but also two unknown HP-IL devices: "KBUSL48" and "DMX1"). I have no idea of the purpose of this program.

If someone is interested, I have the ROM image available on a LIF image file (for Emu71 or for the HP-71B using the PIL-Box/ILPer), with protection removed...

UDL71D     LEX     531 12/16/87 14:52 5.01
UDLMAIN BASIC 22568 12/16/87 14:53 5.01
UDLRTNS BASIC 4654 12/16/87 14:53 5.01
UDLSTR LEX 837 12/16/87 14:54 5.01
UDLCUST LEX 1007 12/16/87 14:54 5.01

Header line of UDLMAIN:



After J-F posted his reply I double checked the ROM. My error !!! When I was with Hughes Aircraft we used Viewtronics terminals also. The printing on the UDL-71* ROM PAC is very small and my imagination and 72 year old eyes morphed it from Viewsonics to Viewtronics. I apologize. John Pierce


Curiouser and curiouser. The display company is actually "Viewsonic" without the trailing "s." Wikipedia's entry on the company says that it was formed in 1987, but that it wasn't called Viewsonic until 1990. So this ROM may have been produced by a company I've never heard of before. The ROM dump shows that this code isn't display related on its face, although I suppose it could turn out to be on closer inspection.

Here's some speculation based again on the name "Viewsonics." Perhaps this is a data collection component for a system designed to visualize audio data?


P.S. Obviously you aren't the only one to get confused over subtle name differences. :)

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